Glow relay tube



9, 1932 HHHHHHHHHHHH ER 1,87l,279

Fi 1 e d J a n 9 1 9 50 NNNNNN OR ATTOR Patentd Aug. 9, 1932 UNITEDhSTATES PATENT OFFICE EARVEY CLAYTON BENTSOHLER, OF EAST CHANGE, NEW J'EBSEY, ASSIGNOR TO 'WEST- INGHO'U'SE LAMP COMPANY, A. CORPOBATION OF PENNSYLVANIA GLOW BELAY TUBE Application filed January 9, 1930. Serial No. 419.524.

This invention relates to an electrical discharge device of the gaseous conducton type and more particularly relates to a device in which the discharge takes place between cold electrodes in a gaseous atmosphere at a reduced pressure.

This invention is an improvement n the device disclosed in my copending application Serial No. 252,437 filed February 7, 1928 and entitled Glow relay tube, from which application a divisional application Serial No. 350,164 was filed on March 27, 1929.

In the glow relay device set forth in the above identified copending applications I have provided means for initiating a glow discharge by positioning a starting anode in close spaced relationship to the cathode upon which may be impressed an electrical potential sufficient to initiate a discharge be.- tween the electrodes. I also provide a main anode adjacent to the starting anode but spaced relatively further from the cathode than the starting anode upon which is mpressed a lower electrical potential substantially approximating the operating potential of the electrical discharge.

The glow relay device such as is disclosed and claimed in the above identified divisional application Serial No. 350,164 has been applied in a number of electrical devices and systems one of which is set forth and claimed in my copending application Serial No. 328,243, filed December 24, 1928 entitled X-ray intensity meter.

In the X-ray intensity meter I pass the rays which may consist of visible light, ultraviolet light, or X-radiations into a discharge device which is sensitive to such X-radiations to cause a small electric current to flow through the device, the amount of the current fiow depending upon the intensity of the X-radiations.

The ray sensitive device is connected to a source of potential and to a condenser of predetermined capacity so that after the ray sensitive device has been subjected to a definite quantity of X-radiations being investigated the condenser will acquire a definite potential. The terminals of the condenser are connected to the terminals of a gaseous conduction device having a definite breakdown potential, such as a gaseous discharge lamp or a glow relay tube. When the condenser has acquired a charge having a potential equal to the breakdown voltage of the gaseous conduction device the condenser discharges through the device and either records the discharge, operates a signal or sets mechanism into operation to terminate the source of the X-radiations.

'It is highly essential in the application of X ray, ultraviolet ray and the like radiations for medicinal purposes to definitely measure the amount of or the time of exposure of the patient thereto.

I have found that when a device of the glow relay type is employed in the specific combination of elements, as set forth in the intensity meter device of copending application Serial No. 328,243 above identified, that the sensitivity of the device is materially altered through electrical leakages and that the specific structure of the device and assembly of elements therein, which are set forth in copending application Serial No. 350,164 above identified must be altered in order to eliminate such electrical leakage.

Before further disclosing the nature of my invention reference should be had to the accompanying drawing wherein,

Fig. 1 is a side elevational view of a glow discharge tube constructed in accordance with the invention set forth in copending application Serial No. 350,164 having the enclosing glass envelope broken away and the cathode shown in cross section to illustrate the constructional features of the device;

Fig. 2 is a. side elevational view of the same device constructed in accordance with the present invention having the enclosing 'glass envelope broken away and-the cathode shown in cross section.

In accordance with the present invention I have found that there is an electrical leakage between the starting or closer spaced anode of the glow relay tube and the cathode which takes place between the closely spaced leading in wires. The leakage path may lie either alon the glass surfaces or through the insulatmg material of a common base l ,i member of the device. This leakage can only be eliminated by bringing the starting anode 'leading in supportwre through the enclosing .glass envelope at a oint remote from the common ress of the evice and a common base mem er ma not be employed.

As constructe in accordance with the invention set forth in my prior application and as set forth in Fig. 1 of the drawing attached hereto, the glow relay tube is comprised of an enclosing glass envelope 1 and a cylindrical cathode 2 of relatively large diameter, a starting anode 3 and a control anode 4, a starting tip 5 integral with cathode 2 and positioned in close spaced relationship to starting anode 3, the leading-'in support wires of cathode 2, starting anode 3 and control' anode 4: passing through press 6 into a base 7 from thence into pins 8. The interior surface of the cathode may be coated with a sputtered layer of an electropositive metal such as misch metal or the alkali metals.

According to the present invention the leading-in support wire 9 for the control anode 3 is removed entirely from the common press 6 of the device and is brought into the device through the enclosing glass envelope 1 at a point remote from the press 6, such as is indicated in Fig'. 2.

I preferably employ a dummy support wire 10 for the control anode 3 which is extended from the 'press 6 and sealed therein to assist in the positioning of the anode 3. It has been found that in the course of manufacture the interior surface of the enclosing glass envelope 1 is substantially degasified and cleansed of the deleterious electrically conductive film thereon and that electrical leakage between closely spaced electrodes or support wires from thi's source is usually not experienced'. The exterior surface of the envelope is not so cleaned and the usual electrical leakage is obtained across this eXterior surface and not the interior surface. I may therefore employ a support wire in the manner herein shown but to prevent electrical leakage the leading-in wire must be brought through the envelope at a point remote from the leading-in wire to the a cathode element to prevent electrical leakage through the exterior electrically conductive film usually present on glasses.

I may conprise one or both electrode'tips 3 and 4 of a highly reactive rare refractory metal such as thorium, titanium, uranium and the like, which metals have the property of reducing the potential required to initiate an electrical discharge between the anode electrode and cathode. A gas pressure of an 8 m. m. mercury and argon gas pressure inv the device a spacing of 'about 1.0 m. m. is preferred between the cathode starting tip 5 and starting anode3. With this specfic ar.. rangement of elements the electrical leakage of the charge accumulatin in the condenser of the ray intensity meter evice of the above identified copending application Serial No. 328,243 through and across the glass o'f the press of the device or between the leadin -in wires through the base member thereo is substantially eliminated and the reliability and accuracy of the intensity meter device incorporat ing the same materially increased.

Having broadly and specifically set forth the nature of the present invention it `is apparent that there may be many variations made of the specific embodiment herein dis-' closed Without departing from the nature ofleading-in conductor for said cathode being* sealed into the envelope at a point opposite the position where the leading-in conductor for the starting anode is sealed whereby electrical leakage between the leading-in conductors for said cathode and starting anode is prevented.

2. A glow relay devicecomprising an envelope having a press, a cathode of relatively large area, a main anode spaced from said cathode and a starting anode also spaced from said cathode, the distance between said starting anode and said cathode being less than the distance beteween the main anode and the cathode, a plurality of lead in wires connected to said anode and said cathode, sealed in said press and extending outside the lower portion of said envelope, a support wire sealed to said press and to said envelope atua point remote from said press,

'said support wire supporting said starting anode and being in electrical connection therewith.

In testimony whereof, I have hereunto subscribed my name this 7th day of January,

HARVEY CLAYTON RENTSCHLER.

inert gas such as argon at from 5 to 8 millimeters mercury pressure may be employed, the specific pressure employed depending in part upon the particular gas and the electrode spacing employed.

With thorium electrodes and from 5 to 

